This invention relates to an oven door opening/closing device for microwave oven.
As a conventional door opening/closing device for microwave oven, there is, for example, disclosed in Japanese official laid open patent pubication No. Sho 58-48391. The door opening/closing device of microwave oven disclosed in said publication, as shown in present FIG. 1 to FIG. 3, comprises a door 4 which may be freely opened and closed at a front opening of a heating chamber 2 defined within microwave oven 1, sash or frame 6 integrally formed by synthetic resin and the like for carrying the door, and a control panel 7 disposed in the sash 6. The control panel 7 includes a timer 8 for setting a cooking time period, cooking button 9 for starting the cooking, and pilot lamp 10 for indicating a cooking mode. Said door 4, as shown in FIG. 1, is rotatably mounted by a pair of hinge pins 12(refer to FIGS. 2 and 3) and is guided by door arms 13, 13' when being opened and closed. The arms 13, 13' are connected to a pair of guide rollers 14 for guiding the door arms 13, 13'. the door arms 13, 13' are constantly urged to the door-closing direction by a pair of door springs 15. As shown in FIG. 2, door metal plate 16 for sealing the microwave is fixed to an interior metal plate 18 of the door by screws 17 to thereby form a choke 19 for sealing the microwave around an internal periphery of the door 14. The plate 16 makes surface contact with metal plate 20 upon opening of the heating chamber 2 to thereby execute the microwave sealing. Cover body 29 integrally formed of synthetic resin is arranged at an opening 21 of said choke 19 formed at internal periphery of the door 4 and is arranged such that one end thereof slides along a surface 32 of the sash 6 when the door is opened and closed. The surface 32 is curved to thereby reduce the resistance of cover body 29 during a door opening operation. And, front surface plate 23 of the door 4 is fixed to the internal metal plate 18 by screws 24, and said internal metal plate 18 covers a gap 28 present along the lower edge of the oven, because bottom end portion 30 of the cover body 29 is mounted so s to extend across the gap 28 in either of the opened or closed state of the door 4.
By the way, according to the door opening/closing device of thus constructed microwave oven, when the door 4 is opened, since the bottom end portion 30 of the cover body 29 is in contact with metal plate 20 and covers the gap 28 between the bottom portion surface 27 of the door 4, the entry into the gap 28 of dregs of cooked food or other foreign substance is prevented, and the cleaning is also convenient because any spilled material lands on the cover body 29, However, since the guide roller 14 and the door arms 13, 13' are separately formed, there have been various problems that much time and effort are required for precisely assembling these items during mass production and at the same time a space must be provided for door spring 15 and also noise is produced by the expansion or contraction of the door spring 15 in response to the door opening/closing as well as by the travel of the guide roller 14.
Moreover, since opening/closing of the door 4 is controlled by the door spring 15, the action is not so natural, and as shown in FIG. 1, in a state that the door 4 is fully opened, the door arms 13, 13' are exposed. Hence, a container of food or a hand of user may strike those arms when putting in or taking out the cooking food.